Process of refining oil.



GEORGE M. HOLBROOK, OF CHICAGO, ILLINOIS, ASSIGNOR TO ARMOUR. ANDCOMPANY, I OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

To all whom it may concern:

No Drawing.

Be it known that I, GEORGE M. HoLBRooK, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Processes of RefiningOil, of which the following is a specification.

This invention relates to improvements and features of novelty in theprocesses of refining oil, and more particularly relates 'to thepurifying of crude cottonseed oil for various industrial and foodpurposes, whereby to procure desirable qual1t1es of refined oil ofhigher grade as to color with less manipulation and with a smallerrefin-- .ing loss than has been possible by other known methods.

It has heretofore been proposed, as for example, in United States PatentNo.

1,007,642, granted October 31, 1911, ,to refine crude cotton-seed oil byfirst treating the oil with an aqueous solution of a water solublealkalinesilicate, such for example, as sodium tetrasilicate, until theacidity of the oil is approximately overcome and then subjecting it tothe action of an alkaline hydroxid, such for example, as sodiumhydroxid, which brings about a precipitation of the soap-stock. Such amethod as this has certain objectionable features, because sodiumsilicate seems to have a chemical effect upon the coloring matter in thecrude oil which renders it more or less immune to further decolorizationduring the secondary treatment. Y i

The main object of the present invention is the provision of a method orprocess which will permit the purification of crude cotton-seed oil insuch a way as to result in an oil of the desired color and with aminimum of refining loss. In order to do this, in view of the discoveryof the detrimental action of the sodium silicate referred to, it isnecessary to avoid the wellknown process specified above of treating theoil first with sodium silicate and then with sodium hydroxid.

In accordance with the principles of the present invention, the crudecotton-seed oil is treated initially with sodium hydroxid and then witha mixture of sodium hydroxid and sodium silicate, thisprocess having theadvantage over the others'that the neutralizing of the free fatty acidsout of Specification of Letters Patent.

namely 44 Baum,

Patented J an. 25, 1916.

Application filed November 15, 1915. Serial No. 61,503.

contact with the silicate prevents the setting of the color, which, ifit occurred, would be difiicult or impossible to remove underfurthertreatment. Under this process, a portion'of the color is removedduring the first step and another portion during the second step, thesodium hydroxid constituting the vital or real refining agent, thesilicate being used as a compacting or condensing agent for the foots orsoapstock, to reduce the amount of neutral oil in such foots, or, stateddifierently, to diminish the refining shrinkage.

The manner of performing this improved process, the percentages ofingredients employed, the temperatures reached, etc., depend upon thenature of the crude oil to be purified and the color to be attained inthe refined product. We may assume, however, a typical case in which thecrude cotton-seed oil has 1% of free fatty acids. To this oil is added1%by weight of a suitable solution of caustic alkali, such as sodiumparticles of the oil with the caustic alkali to thoroughly neutralizethe free fatty acids, which are always present in crude cotton-seed oil.Then a mixture of an aque-z ous solution of sodium hydroxid and anaqueous solution of sodium, silicate composed of 3% by .weight of theoil treated, 18 Baum, sodium hydr'oxid or its equiva: lent and of 1% byweight of the oil treated of sodium silicate of commercial grade,

perature of about 80 Fahrenheit, the temperature of the oil. and itscontained solutions is slowly raised to about 115 Fahrenheit, whereuponthe soap-stock will separate readilv and completely from the refinedoil, which will be of much clearer and lighter color than in the crudestate. In carrying out this process, the original caustic soda solutionneutralizes all, or prac' tically all of the fatty acids, of the causticpreferably being used for this purpose of assuring completeneutralization, and it also precipitates a portion of the coloringmatter and other impurities. The soap-stock is not.permitted to settleat this time, as it would ordinarily, until the silicate is introduced,which appara slight excess is added. After agitation for about 15minutes at an initial tem- 45 a vegetable and animal oils, and is notlimited ently, has the roperty ofcombining with the products 0 theprevious refination and thereby the soap-stock thus formed settles in acompact, glassy condition, which more readily expresses the oil' andforms a soa -stock which separates from the oil easily y reason of. itsincreased specific gravity. lhe a itation is continued after thesilicate is a ded until the, proper temperature is reached for theseparation of the soap-stock in order to assure a complete intermixtureof the ingredients. Stated somewhat differently, b carr ing out theprocess in the two steps, as in icated the final soap-stock or foots isprecipitate in a compact, plastic, or glassy condition which tends toliberate 1part of the oil which might otherwise.

be he d in suspension mechanically.

As has been indicated above, the free fatty acids of'the oil areneutralized before the silicate is used, as the employment of suchsilicate in any considerable proportion or by itself in contact with thecrude cottonseed oil containing such free fat't acids has a deleteriouseffect upon the co or, which necessitates the use of a larger percentageof sodium hydroxid in the subsequent treatment inorder to produce arefined oil of the desired color or it may be impossible to overcome theprejudicial effect on the color,-

: ing material. B this process, as has been cate on t explained suchinjurious effect of the sililie coloring, is prevented by firstneutralizin the free fatty acids with the sodium hy roxid.-

To those skilled in this art it-will be clear that various minor changesmay be made in the process outlined herein without departure from thesubstance of the invention or the sacrifice of any of its advantages.

In the particularprocessoutlined above the refining or purifyin seed oilhas been referre to, but it is to be understood that the process issusceptible of satisfactory use in connection with many to thecotton-seed oil mentioned.

I claim: 1. The process of refining crude cottonseed oil and the likeconsisting in substantially neutralizing tli of crude cottons free fattyacids of the oil by caustic alkali, then treating the oil with a mixtureof caustic alkali and a silicate, and separatin the refined oil from.the soap-stock forme substantially as described.

2. The process of refining crude cottonseed oil and the likeilconsistingin substantially neutralizing t e free fatty acids of the oil by anaqueous solution of caustic alkali, then treating the oil With a mixtureof an aqueous solution of causticalkali and an aqueous solution of asilicate, and separatingthere'fined oil from the soap-stoc formed,substantially as described.

3. The process 0 refining crude cottonseed oil and the likeilconsistingin substan- 1 seed oil and the likeilconsisting in substantiallyneutralizing t efree fatty acids of the oil by a sodium hydroxidsolution,then

subjecting the oil to a mixture of an aqueous solution of sodiumhydroxid and an aqueous solution of sodium silicate, and separating therefined oil from the soap-stock or foots produced, substantially asdescribed.

5. The process of refining crude cotton-' seed oil and the like havingapproximately 1% of free fatty acids, consisting in adding to the crudeoil approximately 1% by weight of a sodium hydroxid solution, 18 Baum,

and agitating the same until the free fatty acids are substantiallyneutralized, then adding a mixture of approximately 8% by weight of theoil treated of an aqueous solution of sodium hydroxid, 18 Baum, andapproximately of 1% by weight of the oil treated of an aoueous solutionof sodium silicate, 44 Baum, agitating the mixture,

and slowly raising the temperature to approximately 115 Fahrenheit, andthen separating the refined oil from the soap-stock produced,substantially as described.

GEORGE ,M. H'OLB'ROOK'.

